论文题目：Carbon-confined ultrasmall T-Nb2O5 nanocrystals anchored on carbon nanotubes by pyrolysing MLD-niobiumcone films for enhanced electrochemical applications

论文作者：Shengyun Zhu, Yuji Yang, Junqing Liu*, Jiaming Sun

发表期刊：Journal of Materials Chemistry A, 8(47), 25371-25381, 2020

Abstract： 

Nb2O5 electrode materials encounter a great challenge for  electrochemical applications due to their poor electrical conductivity  and undesirable thermal sintering. The emerging molecular layer  deposition (MLD) technique provides a feasible route to solve the  problems in the synthesis and application of materials. In this work,  conformal ultrathin niobiumcone films with a high carbon content are synthesized oncarbonnanotubes (CNTs) by MLD using niobium ethoxide and hydroquinone. Nb2O5 nanocrystals and amorphous carbon (AC) are produced during the subsequent pyrolysis of niobiumcone films under nitrogen. More importantly, Nb2O5 nanocrystals are both confined in the carbon shell and anchoredon the surface of carbonnanotubes  to form an (AC@Nb2O5)/CNTs composite. This structure contributes to  suppress the undesirable sintering of Nb2O5 for achieving a small  nanocrystal size and uniform particle dispersion. Therefore, the  (AC@Nb2O5)/CNTs composite shows great potential as an anode material in  lithium/sodium-ion batteries and supercapacitors. As an electrochemical  application evaluation, orthorhombic (AC@Nb2O5)/CNTs-800 with a  nanocrystal size of similar to 6 nm exhibits high specific capacity,  excellent cycling stability and superior rate capability. The enhanced  electrochemical performance is attributed to the synergistic effect of  material characteristics including the optimization of the crystal phase  for efficient lithium ion intercalation, the downsizing of nanocrystals for a short ions/electron transport path, the introduction of carbon materials for high electrical conductivity, and the encapsulation/anchoring of nanocrystals  for high interfacial/structural stability. This work provides a  significant insight into the reasonable design of advanced electrode  materials for high-performance lithium/sodium-ion storage.